problem with connection to Motorola Roadster Pro with iphone 6 version 10.1.1

pairing the motorola car speaker was easy . Incoming calls work fine with instructions in American accent.
Outgoing call via button on speaker loses connection with phone after 1 second.
Using home button to activate "voice control" on the phone maintains connection. Instructions are then with an english accent. Obviously this is not an option when driving!
I presume there are two voice apps working in conflict here, any idea on how I can solve this?